1. Field of the Invention
The present invention relates to male coupling members of pipe couplings and, more particularly, to a male coupling member having an on-off valve.
2. Description of the Related Art
There is a male coupling member having a tubular coupling body having a through-hole extending from a front end opening to a rear end opening, and an on-off valve set in the coupling body. The front end opening of the coupling body is defined by an inner peripheral surface of a uniform diameter that extends a short distance rearward from the front end surface of the coupling body. The on-off valve has a valve member urged forward by a spring member. The outer peripheral surface of a front end portion of the valve member is fitted into the inner peripheral surface of the front end opening of the coupling member. In this state, the on-off valve is placed in a closed position. (See Patent Literature 1)
In the above-described male coupling member, the on-off valve is brought into an open position as a result of the valve member being pushed in rearward by a female coupling member to be connected with the male coupling member.
However, when a high-pressure fluid remains in the male coupling member, the residual pressure may prevent the valve member from being moved even if an operator tries to connect the male and female coupling members to each other. In such a case, the operator usually moves the valve member rearward by hitting the front end surface of the valve member with a hammer or the like, thereby allowing the residual pressure to escape.
However, when the valve member is hit with a hammer as stated above, the valve member may tilt, failing to move parallel to the axis of the tubular coupling body, resulting in the peripheral surface of the valve member biting into the peripheral wall surface of the front end opening of the coupling body. The valve member in such a condition cannot be moved with a hammer or the like. Consequently, the coupling member may become unusable, causing a serious hindrance to the operation.